4-hydroxy-5-aminomethyl-1,3,3a,7-tetraazaindenes

ABSTRACT

Tetraazaindene compounds having the formula   IN WHICH R represents a hydrogen atom, an alkyl group or an alkylthio group, R&#39;&#39; and R&#39;&#39;&#39;&#39; individually represent a hydrogen atom, a lower alkyl group or together form a 5 or 6 membered heterocyclic ring, Y represents a hydrogen atom or an alkyl, alkylthio, aryl or amino group; and the salts thereof. This invention also describes the preparation of the abovementioned compounds and their use in photographic emulsions.

United States Patent 11 1 Anderson et al.

1451 Sept. 9, 1975 4-HYDROXY-5-AMINOMETHYL-1,3,3A,7-

TETRAAZAINDENES [75] Inventors: George de W. Anderson; Ronald E.

Watts, both of Hatfield Broad Oak, near Bishops Stortford. England [73] Assignee: Minnesota Mining and Manufacturing Company, St. Paul, Minn.

[22] Filed: Apr. 29, 1970 [21] Appl. No.: 33,096

Related US. Application Data [62] Division of Ser. No. 688,022, Dec. 12, 1967, Pat. No.

[30] Foreign Application Priority Data Dec. 9, 1966 United Kingdom 55364/66 52 us. (:1. 260/247.1 L; 260/2475 DP; 260/2564 F;

51 1m. (:1. c071) 295/04 [58] Field of Search 260/2564 F, 256.5 R, 260/2471 L, 247.5

[56] References Cited UNITED STATES PATENTS 7/1948 Heimbach et al 95/7 9/1951 Fry 95/7 2,566,659 9/1951 Fry 95/7 OTHER PUBLICATIONS Yoshihide et 211., Chemical Abstracts, Vol. 69, p. 72475, (1968).

Primary Examiner-Richard J. Gallagher Assistant Examiner-Jose Tovar Attorney, Agent, or FirmAlexander, Sell, Steldt & DeLal-lunt [57] ABSTRACT Tetraazaindene compounds having the formula 7 Claims, No Drawings 1 4-HYDROXY-5-AMINOMETHYL-1,3,3a,7- TETRAAZAINDENES This application is a division of US. application Ser. No. 688,022, filed Dec. 12, 1967 now U.S. Pat. No.

This invention relates to organic heterocyclic compounds and is especially concerned with substituted tetraazaindene compounds which are capable of being used as stabilizers for photographic emulsions.

Tetraazaindene compounds in accordance with the invention can be represented by the general formula:

in which R represents a hydrogen atom, an alkyl or an alkylthio group, R and R" individually represent a hydrogen atom, a lower'alkyl group, or together form part of a 5 or 6 membered heterocyclic ring, andY represents a hydrogen atom or an alkyl, alkylthio, aryl .or amino group; and the salts thereof.

These compounds are useful as stabilizers for photographic emulsions into which they can be incorporated. They also have the advantage over tetrazaindene compounds which are not substituted in the 5 position that they have a greater solubility in aqueous gelatin and so can be more readily incorporated in the emulsion.

The tetraazaindene compounds in accordance with the invention can be prepared by reacting a tetraazaindene compound represented by the general formula:

W== \N/&

in which R and Y are as set out above, with formaldehyde or paraformaldehyde and an amine containing the following general group:

in which R and R" are as set out above,

The reaction is best conducted under substantially non-aqueous conditions in, for example, dimethyl sulphoxide or butanol. Normally about 5 moles of formaldehyde or paraformaldehyde and 10 moles of the amine are used per mole of the tetraazaindene but these proportions are not critical. It is, however, usually important to maintain the reactants at the lowest temperature at which reaction occurs, which is usually between and 90C. The product usually crystallizes out of the resulting solution, by cooling if necessary. In certain instances this is obtained as the free Mannich compound. In other cases, the product crystallizes out as a salt of the Mannich compound and excess of the amine. It is important to remove the salt forming amine to obtain optimum stabilizing effect. This may be achieved, for example, by treating an aqueous solution of the amine salt with an acid forming a sparingly soluble salt of the Mannich compound, or alternatively, the amine salt may be dissolved in the theoretical quantity of aqueous sodium hydroxide and evaporated to dryness at as low a temperature as possible to obtain the sodium salt.

The preparation of tetraazaindene compounds in accordance with the invention will now be illustrated with reference to the following Examples.

EXAMPLE ,1

4Hydroxy-6-methyl 2-methylthiol :3 3a:7- tetraazaindene (419' g.), paraformaldehyde (3.8 g.), and dimethyl sulphoxide (40 ml.) were placed in a flask fitted with stirrer, dropping funnel and condenser. The mixture was warmed to dissolve the tetraazaindene and cooled to room temperature. Diethylamine (26 ml.) was added slowly and the temperature rose to 54C, and was not allowed toexceed 60C. The reaction mixture separated into'two clear liquid phases and the flask was then cooled in cold water.

The colorless precipitate was filtered off, washed with acetone and recrystallized from ethanol. This gave a yield of 6.5 g. of the amine salt in the form of colorless needles having a melting point of l68C.

Analysis: C H N S Calculated for C H N OS-l-HNO 41.9 5.8 24.4 9.3 Found: 420 5.9 23.6 9.5

The presence of the nitrate ion was confirmed and the indicated structure is:

tc n bmcn 3 EXAMPLE 2 Dimethyl sulphoxide (400 ml.)"was placed in a flask fitted with dropping funnel, stirrer and condenser and was heated to 50C. 4-Hydroxy-6-methyl-l:3:3a:7- tetraazaindene (37.5 g.) was then added. When all had dissolved, paraformaldehyde (38 g.) was added and the flask cooled to 30C. Diethylamine (260 ml.) was added slowly and the temperature rose to 53C. and was not allowed to exceed 60C. The reaction mixture separated into two clear liquid phases. The flask was then cooled in cold water and a white precipitate formed which was filtered off and washed with ether to give 66.0 g. of the colorless amine salt having a melting point of 148C. with decomposition.

The amine salt (6.16 g.) was dissolved in 20 ml. of NH sodium hydroxide and the solution evaporated to dryness in vacuum at room temperature. The resulting colorless crystals were washed with acetone and dried to obtain the sodium salt.

The indicated structure of the free acid is:

(c 1-1 u.c11 n EXAMPLE 3 Analysis: C H N S Calculated for C ;,H N -,OS 47.7 6.4 21 4 1916 Found: 47.9 6.6 21 2 19.1

indicated structure:

EXAMPLE 4 4-Hydroxy-6-methyI-Z-methylthio-l :3:3a:7-

tetraazaindene (4.9 g. paraformaldehyde 1.56 g.) and butanol (40 ml.) were placed in a flask fitted with stirrer, dropping funnel and condenser. Diethylamine (2.6 ml.) was added and the reaction mixture heated at 55C. for 30 minutes. The white solid formed was filtered off, washed with acetone and dried to obtain 1.3 g. of colorless rectangular plates which melted with decomposition at l50to 155C.

Analysis: C H N 8 Calculated for C.. .H,,,N,,0S; 51.3 6.8 24.9 1 1.4 Found: 51.1 6.9 24.9 11.5

This product had the indicated structure of the free Mannich compound corresponding to the nitrate described in Example 1.

EXAMPLE 5 4-Hydroxy-6-methyl-l z3z3az7-tetraazaindene (7 .5 g), paraformaldehyde (7.5 g.) and n-butanol (50 ml.) were placed in a flask fitted with stirrer, dropping funnel and condenser. Piperidine (50 ml.) was added slowly and the temperature rose to 54C. This temperature was maintained for one hour, during which time most of the solid dissolved to give a pale yellow solution. The slight residue was filtered off and the butanol removed using a rotary film evaporator to give a viscous oil. The addition of diethyl ether caused this to crystallize and the solid was filtered off. Two recrystallizati ons from a mixture of ethanol and acetone yielded 6 g. of colorless needles melting with decomposition at 214% 218C.

4-Hydroxy-6-methyl-2-methylthiol :3 321:7- tetraazaindene (l 1.8 g.). piperidine (6.5 ml.) 35% formalin (5 ml.), and ethanol (50 ml.)' were placed in a flask fitted with a condenser and stirrer and refluxed for 40 minutes. The solid rapidly dissolved and a white precipitate soon started to form. The reaction mixture was cooled and the white solid filtered off. The products was recrystallized from a mixture of methanol and water to obtain 14 g. of colorless cubic crystals having a melting point of C. with decomposition. 8n

Analysis: C H N S Calculated for C,.,H.,,N .SO.2H 0; 47.5 7.0 21.2 9.8

Indicated structure:

z 21120 c111 N scit EXAMPLE 7 4-Hydroxy-(i-methyl-2-methylthio-l:3:3a:7

tetraazaindcne (19.6 g). paraformaldehyde (15.2 g.) and n-hutanol (80 ml.) were placed in a flask fitted with stirrer. condenser and dropping funnel. Morpholine (87 ml.) was added slowly and the reaction mixture heated at (10%. for 30 minutes during which time all the solid dissolved. The reaction mixture was cooled.

and the white solid which formed was filtered off and washed with ether. The product was found to he the morpholine salt of the required compound. To convert it to the nitrate it was suspended in ethanol and aciditied with 2N nitric acid. When the suspension had all dissolved the product slowly precipitated and after filtering off was recrystallized from a mixtureof acetone and water. This gave a yield of 17 g. of colorless hexagonal plates having a melting point of 192C. with decomposition.

r2 scii EXAMPLE 8 Z-Amino-4-hydroxy-o-rnethyl-l :3:3a:7- tetraazaindene 16.5 g.), paraformaldehyde (6 g.), and dimethyl sulphoxide (100 ml.) were placed in a flask fitted with stirrer. dropping funnel and condenser. Diethylamine (53 ml.) was added slowly and the temperature rose to 44C. The reaction mixture was heated to 55C and this temperature maintained for twenty minutes. During this time the reaction mixture turnedlyellow. mostly dissolved and formed two phases. On cooling white crystals separated and were filtered off, washed with acetone and recrystallized from a mixture of methanol and ether. After a further recrystallization from a mixture of acetone and water, 7 g. of colorless needles were obtained which turned brown but did not melt below 360C.

EXAMPLE-I a 4-Hydroxy-o-methyl-l :3:3a:7-tetraalaindcne I 5 g. palratormaldehyde (o g. and dimethyl sulphoxide (50 ml.) were placed in a flask fitted with stirrer, dropping funnel and condenser. 2-lithylaminoethanol (5() ml.) was addcd and the temperature rose slowly to 43C. with most of the solid material dissolving. After heating for 30 minutes at 55C. all the solid had dissolved to give a faintly yellow solution. Removal ofthe solvent in a rotary film evaporator gave a viscous oil which crystallized on treatment with boiling acetone. The crystals were filtered off. washed with acetone and recrystallized twice from a mixture ofmethanol and acetone to give l() g. of colorless cubic crystals melting with decomposition at l5Zl54C.

Indicated structure:

EXAMPLE l() 4-Hydroxy-2-methylthio-l :3 3a: 7-tetraazaindcnc (9.1 g.) paraformaldehyde (3 g.) and dimethyl sulphoxide (50ml) were placed in a flask fitted with stirrer. dropping funnel and condenser. Diethylamine (26 ml.) was added and the temperature rose to 38C. with most of the solid dissolving and the formation of two liquid phases. After heating at 55C. for 30 minutes the slight residue was filtered off and the liquid evaporated to give a gummy residue which crystallized on stirring with acetone. The solid was filtered off, washed with acetone, and recrystallized twice from a mixture of methanol and diethyl ether. This yielded 1.5 g. of colorless rectangular crystals melting with dccomposition at l7() l72C.

Analysis: C H N 5 Calculated for c,.H,,N -,os-. 40.5 6.4 26.2 12.0 Found: 49.2 6.6 "(1.5 l .4

Indicated structure:

EXAMPLE I l 4-Hydroxy-fi-methyl-Z-phenyll :3:3a:7- tetrazaindenc (11.3 g), paraformaldehyde (3 g.) and dimethyl sulphoxide (50 ml.) were placed in a flask littcd with stirrer. dropping funnel and condenser. Diethylamine ml.) was added and the temperature rose to 49C. The solid present did not dissolve but changed in appearance and remained the same after heating for minutes at 55C. The glistening white plates were filtered off and recrystallized twice from a mixture of methanol and ether to obtain 9 g. of colorless hexagonal plates which did not melt below 360C.

4-Hydroxy-2-methyl-6-methylthio-1:3:3az7- tetraazaindene (9.8 g.), paraformaldehyde (7.6 g.) and n-butanol (80 ml.) were placed in a flask fitted with a stirrer. dropping funnel and condenser. Diethylamine (52 ml.) was added slowly and the temperature rose to 50C. The reaction mixture was heated at 55C. for 10 minutes to dissolve all the solid. The solvent was removed in a rotary film evaporator and diethylether was added to the residue to give a yellow solid. This was recrystallized from a mixture of acetone and water to obtain 8.6 g. of colorless needles which melted at 179 1 81C. with decomposition.

The tetraazaindene compounds in accordance with the invention have been found to be very effective as stabilizers for photographic silver halide emulsions. As is well known. light sensitive silver halide emulsions tend to yield. on development. a deposit of silver in those areas which have not been exposed to light. This deposit, which is commonly termed chemical fog inipairs the quality of the image and. indeed. in certain cases may obliterate the image. The tendency to form this fog is more pronounced when the emulsion is of a highly sensitive type and also when the emulsions are stored under adverse conditions. as. for example. under the conditions of high temperature and high humidity which are met with in tropical countries. In order to counteract the tendency of silver halide emulsions to form this fog it is common practice to add to them soeallcd stabilizers. Most of the compounds used as stabilizers are successful to a high degree in preventing the formation of fog. but many of them suffer from the disadvantage that they reduce the sensitivity of the emulsion and also slow down the rate of development of the photographic image.

The heterocyclic compounds of the invention. on the other hand. although effective in preventing the formation of fog. do not cause any decrease in the sensitivity of the emulsions. and indeed. in some cases they may even increase the sensitivity. It is found that particularly good results are obtained when the substituents Y. R. R and R" in the formulae of the reactants given above each contain not more than 4 carbon atoms.

Best results have been obtained with emulsions containing from 5 mg. to 3.0 g. per gram mole of silver present in the emulsion. The stabilizing compounds will normally be added at the completion of chemical ripening or digestion of the emulsion. although it may sometimes be possible for the addition to take place at an earlier stage in the preparation of the emulsion. At whatever stage is chosen the solids may be introduced by themselves or as solution in inert solvents such as water or ethanol.

The compounds need not necessarily be directly added to the silver halide emulsions in order to give protection to the emulsions against the formation of fog- The compounds have been found effectively to stabilize a layer of silver halide emulsion if that layer is in contact with a layer containing one of the heterocyclic compounds so that at sometime during the manufacture of the photographic film the stabilizer can diffuse into the adjacent emulsion layer. This method of effecting stabilization may be particularly advantageous for photographic films. which contain a number of layers of silver halide emulsion.

The following examples illustrate the stabilizing effeet of the heterocyclic compounds in accordance with the invention on a silver halide photographic emulsion.

EXAMPLE 13 A silver iodobromide photographic emulsion was ripened to about 1.2 micron average grain diameter, then washed and digested in the presence of sodium thiosulphate and gold until it reached its maximum speed. This was divided into portions which were separately treated with 0.5 millimole, 1.75 millimoles and 3.0 millimoles of stabilizer per mole of silver present in the emulsion. The resulting admixture was coated onto a film base and dried. A further sample of the emulsion was coated without addition of stabilizer.

One sample of each coating was kept for four days under normal conditions of temperature and humidity while another sample of each was kept for the same period in an incubator at a temperature of 125F. and a relative humidity of percent (i.e. under accelerated aging conditions which approximate to a comparatively long shelf life under normal conditions and a somewhat shorter shelf life under tropical conditions). The film was subsequently exposed to. light and developed in a standard metolhydroquinone developer. The speed. fog and contrast value (y) were then measured. The results obtained are given below in the Table.

TABLE 4 da \s under 4 days incubation Compound ()uantit ordinar conditions at 125F. and 7(1. R.H.

Millimoles/ mole Ag Fog y Relative Speed Fog 'y Relative Speed .5 above fog (1.5 above fog None (1.16 1.55 1.211 (1.33 1.47 1.13 Compound (1. (1.15 1.8 1.1x (1.1) 1.7 1.2(1 prepared in lixamplc 1.75 (1.211 2.35 1.21 (1.18 1.75 1.22

l (nitrate) 3.6 (1.21) 2.11 1.32 (1.21 (.o 1.23

Ntilli. (1.1. 2.1 1.2() 11.26 1.)(1 1.1: Compound (1.5 1.14 2.3 1.22 (1.18 2.0 1.26

prepared in lixample 1.75 (1.15 2.45 l 22 (1.2() 2.3 1.27

None (1.13 l H 1.06 (1.17 LN (1.)5 Compound (1.13 l 8 H1) (1.13 2.1 1.08 prepared in lzxample 1.75 (1.14 2.1 (1.13 1.4 (1. 18

From these values it will be observed that the unstabililed emulsion. when subjected to a period of high temperatureand humidity. lost speed and gave increased fog. while the speed'and fog of the emulsion sample containing the stabilizers of this invention were ing examples and also a comparison stabilizer which was 4-hydroxy-o-methyl-1:3z3a:7-tetraazaindcne. a commonly used commercial stabilizer. The resulting admixture wascoated onto a film base and dried. A further sample of the emulsion was coated without addiunaffected by such accelerated storage conditions. 35 tion of stabilizer.

()ne sample of each coating was kept for 62 hours MP 14 under normal conditions of temperature and humidity EXA while another sample of each was kept for the same A silver iodobromide photographic emulsion was ripperiod in an incubator at a temperature of 70C. and a ened to about 1.2 micron average grain diameter. then relative humidity of 30 percent (i.e. under accelerated washed and heated in the presence of sodium thiosulaging conditions which approximate to a comparatively phate and gold until the optimum values of fog. conlong shelflife under normal conditions and a somewhat trust and speed were obtained. This emulsion was shorter. shelf life under tropieal conditions). The film cooled rapidly and divided into portions which were was subsequently exposed to light and developed in a separately treated with (1.5 millimole. 1.75 millimoles standard metol-hydroquinone developer. The speed. and 3.0 millimoles per mole of silver present in the fog and contrast value ('y) were then measured. The reemulsion of some of the stabilizers prepared in precedsults obtained are given in the following Table.

TABLE 62 hrs. under ordinary 62 hrs. incubation at Quantit; conditions C. and 30); RB. Compound niillimoles, I

mole Ag Fog Maxi- Relative Speed Fog Maxi- Relative Speed "11.1111 mum Contrast (1.5 above fog Contrast (1.5 above fog None (1.10 1.44 1.58 (1.27 1.37 1.53 Standard 3.0 (1118 1.33 1.64 (1.15 1.46 1.63

Compound prepared in 1.75 (1.1() 1.47 1.56 (1.13 1.3) 1.6) Example 1 (nitrate) Compound prepared in 3.0 (1.14 1 23 1.5() (1.14 1.65 1.57 lixamplc 4 Compound prepared in 1.75 (1.08 1.3(1 1.64 (1.1 l 1.45 1.61 Example 5 Compound prepared in 1.75 (1.12 1.62 1.56 (1.1 l 1.73 l 5) Example 6 (omopund prepared in 1.75 (1.13 1.43 1.58 (1.14 1.57 1.66 lixample 7 Compound prepared in 3.0 (1.13 1 28 1.64 (1.1(1 1.45 1.62

Example 1 T LE Continued (\2 hrs under ordinal (Q hrs. incubation at ()uantit conditions 7ll"('i and 30''? Rilli Compound millimoles/ mole Ag Fog Maxi- Relative Speed Fog Maxi- Relathe Speed mum mum Contrast (L5 nhme l'og (untrast 0.5 above fog Compound prepared in L75 U17 L13 l. \ll 1,]: lv-lN l ()3 Example 10 Compound prepared in us um 1.4x 150 (1,10 1.43 1.4? l-Ixample 1 Compound prepared in L7; 0,1!) 1.30 I54 0. I (v 1.34 L5] Example 12 compound of the formula in which R represent s21 hvdrogen atom, an alkyl group or an alkylthio group, R' and R" individually represent a hydrogenatom. a lower alkyl group or together form a 5 or 6 memhered heterocyelic ring. Y represents a hydrogen-atom or an alkyL alkylthio. or amine group and the salts thereof, with the proviso that R R. R" and Y each contain not more than 4 carbon atoms I 2. The tet'raazaindene compound of claim 1 wherein R and R each are ethyl.

3. 4-Hydroxy-S-piperidinomethyl-fi-methyl-l 3,311.7-

tetraazaindene.

:4, i I 1 4 -Hydroxy-5-( N-ethyl-N-B- hydroethyl )aminomethyl-o-methyll 3.321.7- tetraazaindene. l

5, Z-Methylthiol hydroxy;-morpholinomethyl-6- methyl- 1 .3 3a,'Z-tetraazaindene.; v i

6. 4-Hydroxy5 diethylaminoinethyl-(a-methyll.3.3a,7-tetraazaindene.

7. 2-MethylthioP4-hydroxy-S-diethylaminomethyl-6- methyl- 1 3 3a 7tetraazaindene. 

1. A TETRAAZAINDENE COMPOUND OF THE FORMULA
 2. The tetraazaindene compound of claim 1 wherein R'' and R'''' each are ethyl.
 3. 4-Hydroxy-5-piperidinomethyl-6-methyl-1,3,3a,7-tetraazaindene.
 4. 4-Hydroxy-5-(N-ethyl-N- Beta -hydroethyl)aminomethyl-6-methyl-1,3,3a,7-tetraazaindene.
 5. 2-Methylthio-4-hydroxy-5-morpholinomethyl-6-methyl-1,3,3a,7-tetraazaindene.
 6. 4-Hydroxy-5-diethylaminomethyl-6-methyl-1,3,3a,7-tetraazaindene.
 7. 2-Methylthio-4-hydroxy-5-diethylaminomethyl-6-methyl-1,3,3a, 7-tetraazaindene. 